1. Field of the Invention
This invention relates to a new and improved vocal feedback apparatus and method for use in the treatment of stuttering and other speech and hearing abnormalities.
2. Description of the Prior Art
There are many known devices and methods for aiding persongs having a speech or hearing problem. See generally U.S. Pat. Nos. 3,368,551 and 4,310,002.
It has been known in speech therapy to provide delayed auditory feedback by means of a headphone. See U.S. Pat. No. 4,464,119, Pollock et al., Biomedical Engineering, Vol. 11, No. 12, Dec. 1976, pp. 413-414, and Stuttering: A full cure, PARADE, Sept. 21, 1980, p. 17.
It has been known to provide a switch which permits listening by radio and mastoid bone mediums. French Pat. No. 2,260,133.
U.S. Pat. No. 4,472,833, discloses a system for providing and indication by various means such as a tactile element when the speech rate exceeds a predetermined value.
U.S. Pat. No. 3,267,931 discloses a feedback system which responsive to audio input will provide signals to viable nerves of the facial system.
It has been known in treating certain types of stuttering to measure muscle activity in the lip, chin, larynx and frontalis muscle region and provide an audio signal of a frequency proportional to the level of muscle activity. See Guitar, Journal of Speech and Hearing Research, Vol. 18, No. 4, pp. 672-685, (Dec. 1975).
It has also been known to record surface electromyograms from the larynx, chin, lip and trapezious. The feedback is in the form of a tone generated in response to muscle activity. See Hardyck et al., Feedback of Speech Muscle Activity During Silent Reading: Rapid Extinction, Institute of Human Learning, Univ. of Cal., Berkeley, (Aug. 1967) and Hardyck et al. Science, Vol. 154, pp. 1467-1468, Dec. 16, 1966.
U.S. Pat. No. 4,198,542 discloses a device which can be used either to increase the amplitude of a person's voice by causing a second vocal cord to vibrate at the same frequency as a first cord, or to aid in closng the glottis by increasing the tension of the crico-thyroid muscle and thereby allowing the thyroid cartilege to swing normally. For each use this device uses a pair of transducers and appropriate amplifiers and rectifiers. While this device does utilize transducers, it would not be suitable for use in providing tactile feedback.
Other devices, such as the one disclosed in U.S. Pat. No. 3,626,607, suggest the concept of tactile stimulation. That device amplifies an instructor's vocal utterance and transmits the same through a mechanical transducer to the hands or feet of the recipient by means of a vibrating panel supported on a platform. It does not, however, provide tactile stimulation of or feedback to the glottis.
U.S. Pat. No. 3,453,749 discloses an apparatus and method for use by a speech therapist or instructor in teaching persons having speech abnormalities. That invention involves the electronic amplification of the instructor's vocal utterance and the direct application of amplified vibrations through a throat transducer to the larynx region of the throat. While that device and method are helpful in the treatment of certain types of speech abnormalities, they do not provide a satisfactory solution to the problem of stuttering.
Stuttering is a spasmodic repetition of a vocal utterance as a result of excitement or some impediment. Typically, stuttering is of psychogenic origin and tends to arise particularly during stress during the pre-school years, but it also occurs when a child starts school or with the onset of puberty. Providing tactile stimulation to the laryngeal or glottis region of the throat does not, in and of itself, provide an effective treatment for stuttering. Rather, because of its repetitive nature, to provide an effective treatment for stuttering, tactile feedback of the user's own utterance must be delayed in order to allow the user to utilize the tactile stimulation resulting from his own voice rather than that of a third party.
In spite of these known prior art teachings, there remains a real and substantial need for an effective method and apparatus for the treatment of stuttering and other speech and hearing problems.